ML20206C267

Interim Deficiency Rept (CDR 86-00-03) Re Potential Malfunction of Reactor Protection Sys Permissive P-10 Function Under Stated Circumstances.Initially Reported on 860324.Corrective Action in Incorporated

ML20206C267
Person / Time
Site:	Seabrook
Issue date:	05/07/1986
From:	Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:	Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
(CDR-86--3), (CDR-86-00-03), CDR-86--3, SBN-1037, NUDOCS 8606190439
Download: ML20206C267 (3)

Text

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is " f SEABROOK STATION Engineering Office e ) (-% __

E May 7, 1986 SBN- 1037 Ptb5c SeMce of New Hampshire T.F. Q2.2.2 Nnw Hampshire Yankee Division United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Attention: Mr. Richard W. Starostecki, Director Division of Project and Resident Programs

References:

(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 I

(b) Telecon of March 24, 1986,,W. H. Reed (YAEC), P.

Christof akis (YAEC) to K.. Gibson (Region I)

(c) Westinghouse Letter NS-NRC-86-3108 of February 27, 1986 from E. P. Rahe (W) to J. M. Taylor (NRC) nu bject: Interim 10CFR50.55(e) Report: Potential. Malfunction of P-10 Permissive (CDR 86-00-03)

D,mr Sir:

! On March 24, 1986, we reported a 10CFR50.55(e) item to Region I

[ Reference (b)]. The following information is provided under the re-l porting requirements of 10CFR50.55(e).

Description of Deficiency When neutron flux is above P-10 setpoint and if an inoperable channel is placed in the tripped status while the plant is at power "

and the power level is later reduced below the P-10 setpoint, the protective system functions will be disabled if we assume a single failure of a P-10 setpoint bistable. With the single failure of a s bistable and a tripped channel bistable already existing, the P-10 Permissive would not correctly change state due to the fact that the two out of four logic for blocking these functions would remain in effect. Therefore, the P-10 Permissive will not reset automatically as it is, supposed to, thus preventing the reactor to trip when necessary.

Analysis of Safety Implications For accidents involving boron dilution (Modes 2 through 6) or uncontrolled bank withdrawal, licensing bases of the FSAR (operator action time and DNBR, respectively) might not be met.

8606190439 860507 PDR ADOCK 05000443- / e' S PDR .

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SeabrookStationConstructionFieldOffice . P.O. Box 700 . Seabrook,NHO3874 A

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United States Nuclear Regulatory Commission Attention: Mr. Richard W. Starostecki Page 2 Status of Investigation i

Corrective action recommendations in Reference (c) have been eval-uated and will be incorporated in plant abnormal and operation procedures as appropriate. Should a power range channel or portion thereof, affecting P-10, become inoperable when reducing power to below the P-10 setpoint, verification will be made by observation of the existing control room bistable status lights, permissive status lights and associated alarms that the P-10 permissive properly changes state. In addition, reason-able attempts will be made to regain source range instrumentation if the source range (s) are inoperable.

We will notify you when this action is complete.

Very truly ours, t

i John DeVincentis Director of Engineering cc: Atomic Safety and Licensing Board Service List i

Dicne Curran. E quire Calvin A. Canneg'  !

Marmon & Weiss City Manager 2001 S. Street N.W. City Nall -

suite 430 126 Daniel Street Washington, D.C. 20009 - Portsmouth, NN 03801 I

Sherwin E. Turk Esq. Stephen E. Norrill, Esquire ]

Office of the Executive Legal Director Attorney General ,

U.S. Nuclear Regulatory Commission George Dana Bisbee, E, squire Tenth Floor Assistant Attorney General Washington, DC 20555 Office of the Attorney General '

25 Capitol Street Robert A. Backus. Esquire Concord, W 03301-4397 116 Lowell Street P.O. Box 516 Nr. J. P. Nadeau Manchester NN 03105 Selectmen's Office 10 Central Road Philip Ahrens. Esquire Rye, NH 03470 Assistant Attorney General Department of The Attorney General Mr. Angie Nachiros Statehouse Station M Chairman of the Board of Selectmen kugusta,NE 04333 Town of Newbury Newbury, NA 01950 Mrs. Sandra Cavutis Chairman, Board of Selectmen Mr. William S. Lord RFD 1 - Box 1154 Board of Selectmen Kennsington, MN 03027 Town Hall -- Friend Street Amesbury, NA 01913 i Carol S. Sneider. Esquire  !

Assistant Attorney General Senator Gordon J. Numphrey I Department of the Attorney General 1 Pillsbury Street One Ashburton Place,19th Floor Concord, MN 03301 Boston, MA 02108 (ATTN: Norb Boynton)

Senator Gordon J. Husphrey N. Joseph Flynn Esquire U.S. Senate Office of General Counsel , j Washington, DC 20510 Federal Beersency Nanagement Agencyg )

(ATTN: Tom Bucack) 500 C Street SN ' ,

l Washington, DC 20472 t Richard A. Nampe. Esq.

Nampe and McNicholas Paul McBachern. Esquire I 35 Pleasant Street Matthew T. Brock, Esquire Concord, NN 03301 Shaines & NcBachern 25 Naplewood Avenue Donald S. Chick F.O. Box 360 Town Manager Portsmouth, EN 03801

, Town of Exeter Gary W. Holmes, Esq.

10 Front Street Exeter, EN 03833 Holmes & Ells 47 Winnacunnet Road Brentwood Board of Selectmen Hampton, NN 03041 RFD Dalton Road Brentwood, BN 03833 Nr. Ed Thomas FEMA Region I Peter J. Mathews, Mayor 442 John W. McCormack PO & Courthouse City Hall Boston, MA 02109 Newburyport, MA 01950

. Stanley W. Knowles, Chairman l Board of Selectmen F.O. Box 710

• North Hampton, NH 03862

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